1. Field of the Invention
The present invention relates to a communication apparatus, a communication apparatus control method, and a storage medium, which perform data communication using a call control server.
2. Description of the Related Art
Heretofore, a method has been known in which a session is established using a call control protocol such as session initiation protocol (SIP) or the like to perform data communication. SIP is a protocol used for communication such as Internet Protocol FAX (IPFAX) or the like (see Japanese Patent Laid-Open No. 2005-094662).
FIG. 10 illustrates a communication sequence using an existing SIP. FIG. 10 describes a case where a transmission side multifunction peripheral (MFP) and a reception side MFP perform call control via an SIP server, and the transmission side MFP facsimile-transmits image data to the reception side MFP, as an example.
In step S1001, the transmission side MFP transmits “INVITE” to the SIP server. “INVITE” is a session initiation request conforming to SIP. The SIP server which has received the “INVITE” transfers the “INVITE” to the reception side MFP in step S1002, and also returns “100Trying” to the transmission side MFP in step S1003. “100Trying” means that processing according to “INVITE” is being executed.
In step S1004, the reception side MFP which has received the “INVITE” returns “100Trying” to the SIP server. In step S1005, the reception side MFP returns “180Ringing” to the SIP server. “180Ringing” means that a phone is currently being called, and means that a ringback tone is ringing in the case that the device on the reception side is an IP phone. The SIP server which has received the “180Ringing” from the reception side MFP transfers the “180Ringing” to the transmission side MFP in step S1006.
In step S1007, the reception side MFP returns “200OK” to the SIP server. The “200OK” mentioned here means that the reception side MFP has gone into a state in which a session is ready to be established, and in the case that the reception-side device is an IP phone, means that the user has picked up the receiver (off-hooked). The SIP server which has received the “200OK” from the reception side MFP transfers “200OK” to the transmission side MFP in step S1008.
In step S1009, the transmission side MFP transmits “ACK” to the SIP server. “ACK” is a confirmation response as to the “200OK”. The SIP server which has received the “ACK” from the transmission side MFP transfers the “ACK” to the reception side MFP in step S1010. According to the above processing, a session has been established between the transmission side MFP and the reception side MFP, and data communication (transmission of facsimile data) is performed in step S1011. Note that the data communication in step S1011 is performed by peer to peer without going through the SIP server.
In step S1012, the transmission side MFP transmits “BYE” to the SIP server. “BYE” means communication termination (request for session disconnection). The SIP server which has received the “BYE” from the transmission side MFP transfers the “BYE” to the reception side MFP in step S1013. The reception side MFP returns “200OK” to the SIP server in step S1014. The “200OK” mentioned here means that disconnection of the session has been successful. The SIP server which has received the “200OK” from the reception side MFP transfers the “200OK” to the transmission side MFP in step S1015.
According to the above sequence, the transmission side MFP and reception side MFP can perform call control via the SIP server, and facsimile-transmit image data from the transmission side MFP to the reception side MFP.
MFPs in recent years include, in order to reduce power consumption at the time of standby, a sleep mode (power-saving mode) with smaller power consumption than that of a standby mode (normal power mode). Further, the MFPs can also automatically go into the sleep mode in the case that long period of time has elapsed without operations or communication by a user. In a state going into the sleep mode, power supply to the main controller is stopped while continuing power supply to the sub controller (communication unit) of the MFP. Since power supply to the sub controller is continued, the main controller can be activated (return to the normal power mode) in response to a packet from a network.
On the other hand, according to the above SIP technology, a call connection may be cancelled after the SIP server transfers the “INVITE” to the reception side device in the case that there is no response from the reception side device within predetermined time. There may be a case where this predetermined time is set to four seconds, depending on the types of SIP server. Description will be made regarding a problem that will be caused in the case that an MFP including the above sleep mode is used in such an environment, with reference to FIG. 11.
In step S1101, the transmission side MFP transmits “INVITE” to the SIP server. The SIP server which has received the “INVITE” transfers the “INVITE” to the reception side MFP in step S1102, and also returns “100Trying” to the transmission side MFP in step S1103.
In step S1104, the sub controller of the reception side MFP which has received the “INVITE” from the SIP server instructs the main controller to perform activation. In step S1105, the main controller performs activation processing. Upon the main controller being activated, in step S1106 the sub controller transfers the “INVITE” to the main controller. The main controller which has received the “INVITE” returns “100Trying” to the SIP server in step S1107.
Here, it may take five to six seconds for the activation processing of the main controller of the MFP in step S1105. In this case, it takes four or more seconds since the “INVITE” in step S1102 until the “100Trying” in step S1107, and consequently, the call connection is cancelled by the SIP server. In this case, the processing from the transmission of the “INVITE” in step S1101 has to be performed again, which is poor in operating efficiency.